Remind me... It's Just a Phase!?!

Thornton has reached the “terrible threes”, I’ve decided. Frankly, I think they had the “terrible twos” incorrectly named. Two wasn’t that bad, but 6 weeks short of our 3rd birthday, I have a sassy, button-pushing, limit stretching child on my hands. Of course, this is between moments of gentleness and giving and “mama, I love you”, so don’t think I’m complaining. I can mostly deal with the sassy, what I am having a challenge with is the aggression. My question is mostly to mammas of boys (I think). How are you reacting to aggressive behavior and at what point are you calming them down? I think it’s mostly just boy stuff: kicking and punching the air for no apparent reason, jumping off pretty much anything he can climb up, and making “roar” sounds….sometimes roars also have teeth bared with aggressive “pretend biting” (not actually biting though). While it sounds sorta benign on paper, it can get pretty intense (and annoying). I “time-out” when we act out on our brother, or mamma or anyone else, but what about the other stuff? I’m just trying to balance letting him “be a boy” (clueless here) with stuff I do need to correct. We’re doing tons of outside play, and opportunity to burn energy, but his seems limitless! Phase? Let it go? Geez… BOYS!!!